code: def __len__(self):
      return len(self.wav_list)
  
file_path: audio/examples/asr/emformer_rnnt/mustc/dataset.py
imports: from pathlib import Path
  from typing import Union
  import torch
  import torchaudio
  import yaml
label_desc: Use image node_id 4 for calling the MUSTC obj's underlying member method code with example usage: obj.__len__() and returns: len